Conditioned taste aversion induced by ethanol in alcohol-preferring rats: Influence of the method of ethanol administration

A recent study of our group has shown that ethanol evokes conditioned place preference (CPP) in Marchigian Sardinian alcohol-preferring (msP) rats fol lowing intragastric (IG) administration by means of an indwelling IG cathet er, but not following administration by gavage or by intraperitoneal (IP) i njection. The present study evaluated in ethanol-naive msP rats the influen ce of the method of administration (IG injection by indwelling catheter vs. IP injection) on ethanol-induced conditioned taste aversion (CTA). The dos e of 0.35 g/kg of ethanol did not evoke aversion either by IG or by IP admi nistration. Following IG injection, 0.7 g/kg of ethanol, the amount that ms P rats voluntarily ingest in a short (2-5 min) drinking episode, did not ev oke CTA, and 1.5 g/kg induced a modest CTA. On the other hand, IP injection of 0.7 g/kg of ethanol evoked CTA, and 1.5 g/kg induced a very pronounced CTA. These findings show that the aversive properties of ethanol in msP rat s are influenced by the method of administration, and suggest that the IG i njection by catheter may reveal more faithfully than the IP injection the m otivational properties of amounts of ethanol that alcohol-preferring rats v oluntarily ingest. (C) 1999 Elsevier Science Inc.